Building walls are constructed with an interior building substructure that is often formed of vertical wood studs and a sheathing material that can be plywood or oriented strand board (OSB), particularly in a residential dwelling, or other known building structural materials, and an exterior covering which can be masonry construction or siding manufactured from vinyl, aluminum, wood and other known materials. This interior building substructure is typically wrapped with a plastic sheeting, such as Tyvek® barriers produced by Dupont, that provide a barrier to the passage of air and moisture to the building substructure. For masonry exteriors, a wire mesh is attached to the protective barrier, such as by stapling, and the masonry covering is added, incorporating the wire mesh to help secure the exterior masonry covering to the interior building structure.
Typically, there is a difference between the ambient atmospheric temperature and the temperature of the interior of the building. This temperature differential can result in the formation of condensation along the protective barrier. In masonry exteriors, particularly stucco and dryvet coverings, the masonry material can absorb the condensation and cause deterioration of the masonry exterior covering. To provide an air space between the exterior covering material and the interior building substructure, a spacer member can be placed between the interior and exterior substructures. This spacer member is intended to provide a drainage path for moisture; however, when the exterior covering material compresses the spacer member, the drainage path is reduced and becomes less effective. Even masonry coverings can result in the collapse of the spacer member as the attachment of the wire mesh to the building substructure can result in the compression of the spacer member, as can the attachment of siding materials to the building substructure.
Trapping moisture is a particular problem with building walls utilizing a protective barrier material wrapped around the building substructure. Some of these protective barrier materials are designed to permit the passage of moisture through the barrier material in one direction so that moisture can escape the building but cannot enter the building. Such moisture vapor permitted to pass through the protective barrier must be provided with a drainage path to prevent the moisture from being trapped within the building wall structure. Thus, these plastic spacer members need to provide a drainage ability on both sides of the spacer member to prevent the accumulation of moisture within the building wall structure.
One form of a spacer member can be found in U.S. Pat. No. 6,298,620, granted to Michael Hatzinikolas on Oct. 9, 2001, wherein the moisture control panel is formed with a number of spaced bosses on one side of the base member and a plurality of downwardly oriented weep holes to allow the passage of moisture from one side of the base sheet to the other. Such a spacer member only provides an effective drainage path on one side of the base sheet. Furthermore, the weep holes or perforations formed into the base sheet can become filled with masonry material that can be applied to the perforated side of the base sheet. In U.S. Pat. No. 5,860,259, granted to Walter Laska on Jan. 19, 1999, a similar spacer member is provided with a porous drain section and an insulating section; however, an air space or drainage path is only provided on one side of the spacer member.
A corrugated plastic film spacer member is disclosed in U.S. Pat. No. 6,990,775, issued to John Koester on Jan. 31, 2006, in which the grooves or channels are vertically oriented to provide vertical drainage paths for accumulated moisture, and in which perforations allow for the flow of moisture from one side of the spacer member to the other. In the Koester spacer member, a sheet of water resistant material is preferably attached by adhesive to the outer side of the spacer member to keep masonry material from plugging the channels and preventing the passage of moisture along the channels. The corrugated shape of the undulating ridges and channels are not resistant to compression when exterior materials are nailed or stapled to the interior building substructure. Thus, contractors utilizing such a spacer member would need to be careful of crushing the spacer member when applying the exterior covering materials.
The spacer material in U.S. Pat. No. 6,761,006 granted on Jul. 13, 2004, to John Lubker, and other related patents, such as U.S. Pat. No. 6,869,901, granted on Mar. 22, 2005, are directed to a woven type of a drainage wrap material that is capable of being rolled and applied like the protective barrier on the interior building substructure. The Lubker drainage wrap material provides a three dimensional spacer function while the woven nature of the material allows the passage of moisture from one side of the drainage material to the other. This type of drainage wrap material is subject to being plugged with masonry materials as the outer surface of the drainage wrap material is not conducive to mounting a protective barrier to prevent the passage of masonry materials into the drainage material. As a result, the drainage wrap material can become blocked to prevent the flow of accumulated moisture downwardly.
The spacer material disclosed in U.S. Pat. No. 6,594,965, issued on Jul. 22, 2003, to Michael Coulton is manufactured from a woven fiber material formed in a configuration incorporating vertically oriented ridges and channels. Like the aforementioned U.S. Pat. No. 6,990,775, these channels are not resistant to compression when the exterior covering material is affixed to the building substructure. The formation of the spacer member from woven fiber material is particularly subject to being compressed.
The spacer member disclosed by Michael Coulton in his U.S. Pat. No. 6,786,013, granted on Sep. 7, 2004, does include compression resistant spacer elements that project in opposing directions in a continuous integral formation. While this integral formation of the spacer elements is resistant to compression and does provide a drainage path on both opposing sides of the spacer member, the compression resistant capability is reliant on the interconnected, integrally formed spacer elements. Although this spacer member configuration is capable of being rolled for shipping and handling purposes, the structure of the spacer member does not provide for a good location to form perforations into the spacer member to permit the passage of moisture from one side of the spacer member to the other. Although apertures are disclosed on the apices of the spacer elements, such a location does not provide a good communication from one side of the spacer member to the other. Placing perforations or apertures on the sides of the spacer elements will weaken the integrally formed spacer elements and reduce the compression resistance of the spacer member. Furthermore, the placement of apertures on the apices of the spacer elements restricts the ability to attach a barrier member on the spacer member to prevent the intrusion of masonry material within the valleys formed between spacer elements, and without a barrier member masonry material would fill the spacer voids on one side of the spacer member and disrupt drainage of moisture.
Accordingly, it would be desirable to provide a spacer member for use in constructing exterior walls of buildings to provide drainage paths on opposing sides of the spacer member while providing resistance to compression of the spacer member and the ability to attach an optional barrier member on one side of the spacer member and to incorporate perforations that will allow for flow communication from one side of the spacer member to the other without compromising the compression resistance of the spacer member.